1. Field of the Invention
The present invention relates generally to the fields of blood vessels and tumor biology. More particularly, it embodies the surprising findings that aminophospholipids, such as phosphatidylserine and phosphatidylethanolamine, are accessible, stable and specific markers of tumor vasculature. The invention thus provides therapeutic constructs and conjugates that bind to aminophospholipids for use in delivering toxins and coagulants to tumor blood vessels and for inducing thrombosis and tumor regression.
2. Description of the Related Art
Tumor cell resistance to chemotherapeutic agents represents a significant problem in clinical oncology. In fact, this is one of the main reasons why many of the most prevalent forms of human cancer still resist effective chemotherapeutic intervention, despite certain advances in the field of chemotherapy.
A significant problem to address in tumor treatment regimens is the desire for a xe2x80x9ctotal cell killxe2x80x9d. This means that the more effective treatment regimens come closer to a total cell kill of all so-called xe2x80x9cclonogenicxe2x80x9d malignant cells, i.e., cells that have the ability to grow uncontrolled and replace any tumor mass that might be removed by the therapy. Due to the goal of developing treatments that approach a total cell kill, certain types of tumors have been more amenable to therapy than others. For example, the soft tissue tumors, e.g., lymphomas, and tumors of the blood and blood-forming organs, e.g., leukemias, have generally been more responsive to chemotherapeutic therapy than have solid tumors, such as carcinomas.
One reason for the susceptibility of soft and blood-based tumors to chemotherapy is the greater accessibility of lymphoma and leukemic cells to chemotherapeutic intervention. Simply put, it is much more difficult for most chemotherapeutic agents to reach all of the cells of a solid tumor mass than it is the soft tumors and blood-based tumors, and therefore much more difficult to achieve a total cell kill. Increasing the dose of chemotherapeutic agents most often results in toxic side effects, which generally limits the effectiveness of conventional anti-tumor agents.
Another tumor treatment strategy is the use of an xe2x80x9cimmunotoxinxe2x80x9d, in which an anti-tumor cell antibody is used to deliver a toxin to the tumor cells. However, in common with the chemotherapeutic approaches described above, immunotoxin therapy also suffers from significant drawbacks. For example, antigen-negative or antigen-deficient cells can survive and repopulate the tumor or lead to further metastases. Also, in the treatment of solid tumors, the tumor mass is generally impermeable to molecules of the size of antibodies and immunotoxins. Both the physical diffusion distances and the interstitial pressure within the tumor are significant limitations to this type of therapy.
A more recent strategy has been to target the vasculature of solid tumors. Targeting the blood vessels of the tumors, rather than the tumor cells themselves, has certain advantages in that it is not likely to lead to the development of resistant tumor cells, and that the targeted cells are readily accessible. Moreover, destruction of the blood vessels leads to an amplification of the anti-tumor effect, as many tumor cells rely on a single vessel for their oxygen and nutrients (Denekamp, 1990). Exemplary vascular targeting strategies are described in U.S. Pat. Nos. 5,855,866 and 5,965,132 (U.S. application Ser. No. 08/350,212, Issue Fee paid), which particularly describe the targeted delivery of anti-cellular agents and toxins to protein markers of tumor vasculature.
Another effective version of the vascular targeting approach is to target a coagulation factor to a protein marker expressed or adsorbed within the tumor vasculature (Huang et al., 1997; U.S. Pat. Nos. 5,877,289, 6,004,555 and 6,093,399 (U.S. applications Ser. Nos. 08/487,427 and 08/482,369; Issue Fees paid)). The delivery of coagulants, rather than toxins, to tumor vasculature has the further advantages of reduced immunogenicity and even lower risk of toxic side effects. As disclosed in U.S. Pat. No. 5,877,289, a preferred coagulation factor for use in such tumor-specific thrombogens, or xe2x80x9ccoaguligandsxe2x80x9d, is a truncated version of the human coagulation-inducing protein, Tissue Factor (TF). TF is the major initiator of blood coagulation (Ruf et al., 1991; Edgington et al., 1991; Ruf and Edgington, 1994). Treatment of tumor-bearing mice with such coaguligands results in significant tumor necrosis and even complete tumor regression in many animals (Huang et al., 1997; U.S. Pat. Nos. 5,877,289, 6,004,555 and 6,093,399 (U.S. applications Ser. Nos. 08/487,427 and 08/482,369; Issue Fees paid)).
Although the specific delivery of therapeutic agents, such as anti-cellular agents, toxins and coagulation factors, to protein markers of tumor vessels represents a significant advance in tumor treatment protocols, there is still room for additional vascular targeting therapies. The identification of additional stable targets to allow specific tumor vessel destruction in vivo would naturally be of benefit in expanding the number of targeting options. More particularly, the development of targeting agents for delivering therapeutics even closer to the tumor vascular endothelial cell membrane would represent an important advance.
The present invention addresses the needs of the prior art by providing new compositions and methods for tumor vasculature imaging and destruction. The invention is based, in part, on the finding that arninophospholipid membrane components, such as phosphatidylserine and phosphatidylethanolamine, are accessible, stable markers of tumor vasculature. The invention thus provides binding ligands and antibodies against aminophospholipids that are operatively attached to therapeutic agents, and methods of using constructs in the specific delivery of diagnostics and therapeutics to the actual surface of tumor vascular endothelial cell membranes.
Important aspects of the invention are that therapeutic agents can be delivered in intimate contact with the tumor vascular endothelial cell membrane, allowing either rapid entry into the target cell or rapid association with effector cells, components of the coagulation cascade, and such like. Certain surprising features of the invention include the discovery that translocation of aminophospholipids, such as phosphatidylserine (PS), to the surface of tumor vascular endothelial cells occurs, at least in a significant part, independently of cell damage and apoptopic or other cell-death mechanisms. Thus, PS surface expression in this environment is not a consequence of cell death, nor does it trigger immediate cell destruction.
The discovery of sufficiently stable PS expression on morphologically intact tumor-associated vascular endothelial cells is important to the targeting nature of the present invention. Should PS translocation to the outer surface of tumor vascular endothelium occur only in dying cells, or should it inevitably trigger cell death, then PS expression would be expected to be transient and PS would not likely be a good candidate target for therapeutic intervention. Surprisingly, the present invention shows that significant stable PS expression occurs in viable endothelial cells in a tumor environment, thus providing ample targeting opportunities.
The present invention therefore basically provides methods for delivering selected diagnostic and therapeutic agents to tumor or intratumoral vasculature, comprising administering to an animal having a vascularized tumor a biologically effective amount of a binding ligand that comprises a selected diagnostic or therapeutic agent operatively attached to a targeting agent that binds to an aminophospholipid, preferably one that binds to phosphatidylserine or phosphatidylethanolamine, on the luminal surface of blood vessels or intratumoral blood vessels of the vascularized tumor.
The methods of the invention provide for killing, or specifically killing, tumor or intratumoral vascular endothelial cells, and comprise administering to an animal or patient having a vascularized tumor a biologically effective amount of at least a first pharmaceutical composition comprising a binding ligand that comprises a selected therapeutic agent operatively attached to a targeting agent that binds to an aminophospholipid, preferably one that binds to phosphatidylserine or phosphatidylethanolamine, on the luminal surface of tumor or intratumoral vascular endothelial cells.
The xe2x80x9cbinding ligandsxe2x80x9d of the present invention are thus xe2x80x9caminophospholipid binding ligandsxe2x80x9d, xe2x80x9ctherapeutic aminophospholipid binding ligand constructsxe2x80x9d, xe2x80x9caminophospholipid-targeted therapeutic agentsxe2x80x9d, xe2x80x9caminophospholipid-targeted therapeuticsxe2x80x9d, xe2x80x9caminophospholipid-targeted therapeutic agent constructsxe2x80x9d, or xe2x80x9ctherapeutic agent-aminophospholipid targeting agent constructsxe2x80x9d. For simplicity, these agents are referred to herein as xe2x80x9cbinding ligandsxe2x80x9d or xe2x80x9ctherapeutic agent-targeting agent constructsxe2x80x9d, with the understanding that such terms are used as a succinct way of referring to a conjugate or other operative association of a selected therapeutic agent and a targeting agent, antibody, binding protein or active fragment thereof, that binds to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, expressed on the luminal surface of tumor or intratumoral vascular endothelial cells.
xe2x80x9cBiologically effective amountsxe2x80x9d are amounts of the therapeutic agent-targeting agent construct effective to specifically kill at least a portion, and preferably a significant portion, of the tumor or intratumoral vascular endothelial cells, as opposed to endothelial cells in normal vessels, upon binding to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, expressed on the lurninal surface of the tumor or intraturnoral vascular endothelial cells. As such, it is an xe2x80x9cendothelial cell killing amountxe2x80x9d or a xe2x80x9ctumor vascular endothelial cell killing amountxe2x80x9d of a therapeutic agent-targetingagent construct.
As used throughout the entire application, the terms xe2x80x9caxe2x80x9d and xe2x80x9canxe2x80x9d are used in the sense that they mean xe2x80x9cat least onexe2x80x9d, xe2x80x9cat least a firstxe2x80x9d, xe2x80x9cone or morexe2x80x9d or xe2x80x9ca pluralityxe2x80x9d of the referenced components or steps, except in instances wherein an upper limit is thereafter specifically stated. Therefore a xe2x80x9ctherapeutic agent-targeting agent constructxe2x80x9d means xe2x80x9cat least a first therapeutic agent-targeting agent constructxe2x80x9d. The operable limits and parameters of combinations, as with the amounts of any single agent, will be known to those of ordinary skill in the art in light of the present disclosure.
The xe2x80x9caxe2x80x9d and xe2x80x9canxe2x80x9d terms are also used to mean xe2x80x9cat least onexe2x80x9d, xe2x80x9cat least a firstxe2x80x9d, xe2x80x9cone or morexe2x80x9d or xe2x80x9ca pluralityxe2x80x9d of steps in the recited methods, except where specifically stated. This is particularly relevant to the administration steps in the treatment methods. Thus, not only may different doses be employed with the present invention, but different numbers of doses, e.g., injections, may be used, up to and including multiple injections.
An xe2x80x9caminophospholipidxe2x80x9d, as used herein, means a phospholipid that includes within its structure at least a first primary amino group. Preferably, the term xe2x80x9carninophospholipidxe2x80x9d is used to refer to a primary amino group-containing phospholipid that occurs naturally in mammalian cell membranes. However, this is not a limitation on the meaning of the term xe2x80x9caminophospholipidxe2x80x9d, as this term also extends to non-naturally occurring or synthetic aminophospholipids that nonetheless have uses in the invention, e.g., as an immunogen in the generation of anti-aminophospholipid antibodies (xe2x80x9ccross-reactive antibodiesxe2x80x9d) that do bind to aminophospholipids of mammalian plasma membranes. The aminophospholipids of U.S. Pat. No. 5,767,298, incorporated herein by reference, are appropriate examples.
The prominent aminophospholipids found in mammalian biological systems are the negatively-charged phosphatidylserine (xe2x80x9cPSxe2x80x9d) and the neutral or zwitterionic phosphatidylethanolamine (xe2x80x9cPExe2x80x9d), which are therefore preferred aminophospholipids for targeting by the present invention. However, the invention is by no means limited to the targeting of phosphatidylserines and phosphatidylethanolamines, and any other aminophospholipid target may be employed (White et al., 1978; incorporated herein by reference) so long as it is expressed, accessible or complexed on the luminal surface of tumor vascular endothelial cells.
All aminophospholipid-, phosphatidylserine- and phosphatidylethanolamine-based components are encompassed as targets of the invention irrespective of the type of fatty acid chains involved, including those with short, intermediate or long chain fatty acids, and those with saturated, unsaturated and polyunsaturated fatty acids. Preferred compositions for raising antibodies for use in the present invention may be aminophospholipids with fatty acids of C18, with C18:1 being more preferred (Levy et al., 1990; incorporated herein by reference). To the extent that they are accessible on tumor vascular endothelial cells, aminophospholipid degradation products having only one fatty acid (lyso derivatives), rather than two, may also be targeted (Qamar et al., 1990; incorporated herein by reference).
Another group of potential aminophospholipid targets include, for example, phosphatidal derivatives (plasmalogens), such as phosphatidalserine and phosphatidalethanolamine (having an ether linkage giving an alkenyl group, rather than an ester linkage giving an acyl group). Indeed, the targets for therapeutic intervention by the present invention include any substantially lipid-based component that comprises a nitrogenous base and that is present, expressed, translocated, presented or otherwise complexed in a targetable form on the luminal surface of tumor vascular endothelial cells, not excluding phosphatidylcholine (xe2x80x9cPCxe2x80x9d). Lipids not containing glycerol may also form appropriate targets, such as the sphingolipids based upon sphingosine and derivatives.
The biological basis for including a range of lipids in the group of targetable components lies, in part, with the observed biological phenomena of lipids and proteins combining in membranous environments to form unique lipid-protein complexes. Such lipid-protein complexes extend to antigenic and immunogenic forms of lipids such as phosphatidylserine, phosphatidylethanolamine and phosphatidylcholine with, e.g., proteins such as xcex22-glycoprotein I, prothrombin, kininogens and prekallikrein. Therefore, as proteins and polypeptides can have one or more free primary amino groups, it is contemplated that a range of effective xe2x80x9caminophospholipid targetsxe2x80x9d may be formed in vivo from lipid components that are not aminophospholipids in the strictest sense. Nonetheless, all such targetable complexes that comprise lipids and primary amino groups constitute an xe2x80x9caminophospholipidxe2x80x9d within the scope of the present invention.
The inventive methods also act to arrest blood flow, or specifically arrest blood flow, in tumor vasculature. This is achieved by administering to an animal or patient having a vascularized tumor at least one dose of at least a first pharmaceutical composition comprising a coagulation-inducing amount, or a vessel-occluding amount, of at least a first cytotoxic or agulative agent operatively attached to a targeting agent that binds to an aminophospholipid, eferably phosphatidylserine or phosphatidylethanolamine, translocated to the luminal surface tumor vasculature.
The xe2x80x9ccoagulation-inducing amountxe2x80x9d or xe2x80x9cvessel-occluding amountxe2x80x9d is an amount of the therapeutic agent-targeting agent construct effective to specifically promote coagulation in, and hence occlude, at least a portion, and preferably a significant portion, of tumor or intratumoral blood vessels, as opposed to normal blood vessels, upon binding to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, translocated to the luminal surface of tumor or intratumoral blood vessels. The xe2x80x9cvessel-occluding amountxe2x80x9d is therefore a functionally effective amount, and is not a physical mass of therapeutic agent-targeting agent construct sufficient to span the breadth of a vessel.
Methods for destroying, or specifically destroying, tumor vasculature are provided that comprise administering to an animal or patient having a vascularized tumor one or more doses of at least a first pharmaceutical composition comprising a tumor-destructive amount of at least a first occluding or destructive agent operatively attached to a targeting agent that binds to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, presented on the luminal surface of tumor or intratumoral vasculature. The xe2x80x9ctumor-destructive amountxe2x80x9d is an amount of the therapeutic agent-targeting agent construct effective to specifically destroy or occlude at least a portion, and preferably a significant portion, of tumor or intratumoral blood vessels, as opposed to normal blood vessels, upon binding to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, presented on the luminal surface of the vascular endothelial cells of the tumor or intratumoral blood vessels.
The invention further encompasses methods for treating cancer and solid tumors, comprising administering to an animal or patient having a vascularized tumor a tumor necrosis-inducing amount or amounts of at least a first pharmaceutical composition comprising at least a first therapeutic or necrotic agent operatively attached to a targeting agent that binds to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, on the luminal surface of blood vessels or intratumoral blood vessels of the vascularized tumor. The xe2x80x9ctumor necrosis-inducing amountxe2x80x9d is an amount of the therapeutic agent-targeting agent construct effective to specifically induce hemorrhagic necrosis in at least a portion, and preferably a significant portion, of the tumor upon binding to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, complexed at the luminal surface of the vascular endothelial cells of the tumor or intratumoral blood vessels, while exerting little adverse side effects on normal, healthy tissues.
The methods of the invention may thus be summarized as methods for treating an animal or patient having a vascularized tumor, comprising administering to the animal or patient a therapeutically effective amount of at least a first pharmaceutical composition comprising at least a first therapeutic agent-targeting agent construct that binds to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, present, expressed, translocated, presented or complexed at the luminal surface of blood transporting vessels of the vascularized tumor.
The essence of the invention may also be defined as a composition comprising at least a first diagnostic agent-targeting agent construct, or preferably a therapeutic agent-targeting agent construct, preferably that binds to phosphatidylserine or phosphatidylethanolamine, for use in the preparation of a medicament for use in tumor vasculature imaging and/or destruction and for human tumor diagnosis and/or treatment. This can also be defined as a composition comprising at least a first diagnostic agent-targeting agent construct, or preferably a therapeutic agent-targeting agent construct, for use in the preparation of a medicament for use in binding to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, present, expressed, translocated, presented or complexed at the luminal surface of blood transporting vessels of a vascularized tumor and for use in forming an image of tumor vasculature and/or for use in inducing tumor vasculature destruction and for human tumor diagnosis and/or treatment.
In the methods, medicaments and uses of the present invention, one of the advantages lies in the fact that the provision of the diagnostic or therapeutic agent-targeting agent construct, preferably one that binds to phosphatidylserine or phosphatidylethanolamine, into the systemic circulation of an animal or patient results in the preferential or specific localization to the tumor vascular surface membranes themselves, and not to some protein complex more distant from the membrane. The invention thus provides for more intimate cell contact than the methods and anti-vascular agents of the prior art.
In the context of the present invention, the term xe2x80x9ca vascularized tumorxe2x80x9d most preferably means a vascularized, malignant tumor, solid tumor or xe2x80x9ccancerxe2x80x9d. The invention is particularly advantageous in treating vascularized tumors of at least about intermediate size, and in treating large vascularized tumorsxe2x80x94although this is by no means a limitation on the invention. The invention may therefore be used in the treatment of any tumor that exhibits aminophospholipid- positive blood vessels, preferably phosphatidylserine- and/or phosphatidylethanolamine-positive blood vessels.
In preferred embodiments, the tumors to be treated by the present invention will exhibit a killing effective number of aminophospholipid-positive blood vessels. xe2x80x9cA killing effective number of aminophospholipid-positive blood vesselsxe2x80x9d, as used herein, means that at least about 3% of the total number of blood vessels within the tumor will be positive for aminophospholipid expression, preferably phosphatidylserine and/or phosphatidylethanolamine expression. Preferably, at least about 5%, at least about 8%, or at least about 10% or so, of the total number of blood vessels within the tumor will be positive for aminophospholipid expression. Given the aminophospholipid-negative, particularly PS-negative, nature of the blood vessels within normal tissues, the tumor vessels will act as sink for the administered antibodies. Furthermore, as destruction of only a minimum number of tumor vessels can cause widespread thrombosis, necrosis and an avalanche of tumor cell death, antibody localization to all, or even a majority, of the tumor vessels is not necessary for effective therapeutic intervention.
Nonetheless, in more preferred embodiments, tumors to be treated by this invention will exhibit a significant number of aminophospholipid-positive blood vessels. xe2x80x9cA significant number of aminophospholipid-positive blood vesselsxe2x80x9d, as used herein, means that at least about 10-12% of the total number of blood vessels within the tumor will be positive for aminophospholipid expression, preferably phosphatidylserine and/or phosphatidylethanolamine expression. Even more preferably, the % of aminophospholipid-expressing tumor vessels will be at least about 15%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 80% or so of the total number of blood vessels within the tumor, up to and including even at least about 90% or 95% of the vessels.
The xe2x80x9ctherapeutically effective amountsxe2x80x9d for use in the invention are amounts of therapeutic agent-targeting agent constructs, preferably PS- or PE-binding constructs, effective to specifically kill at least a portion of tumor or intratumoral vascular endothelial cells; to specifically promote coagulation in at least a portion of tumor or intratumoral blood vessels; to specifically occlude or destroy at least a portion of blood transporting vessels of the tumor; to specifically induce necrosis in at least a portion of a tumor; and/or to induce tumor regression or remission upon administration to selected animals or patients. Such effects are achieved while exhibiting little or no binding to, or little or no killing of, vascular endothelial cells in normal, healthy tissues; little or no coagulation in, occlusion or destruction of blood vessels in healthy, normal tissues; and exerting negligible or manageable adverse side effects on normal, healthy tissues of the animal or patient.
The terms xe2x80x9cpreferentiallyxe2x80x9d and xe2x80x9cspecificallyxe2x80x9d, as used herein in the context of promoting coagulation in, or destroying, tumor vasculature, and/or in the context of causing tumor necrosis, thus mean that the therapeutic agent-targeting agent constructs function to achieve coagulation, destruction and/or tumor necrosis that is substantially confined to the tumor vasculature and tumor site, and does not substantially extend to causing coagulation, destruction and/or tissue necrosis in normal, healthy tissues of the animal or subject. The structure and function of healthy cells and tissues is therefore maintained substantially unimpaired by the practice of the invention.
Although understanding the mechanism of action is not necessary to the practice of the present invention, the methods will generally operate on the basis of the mode of action of the particular therapeutic agent or agents chosen for attachment to the targeting agent. As such, the aminophospholipid binding agents that are conjugated to, or operatively associated with, cytotoxic or anticellular agents (xe2x80x9canti-aminophospholipid immunotoxinsxe2x80x9d) will act initially via cellular destruction. Likewise, aminophospholipid binding agents that are conjugated to, or operatively associated with, coagulation factors (xe2x80x9canti-aminophospholipid coaguligandsxe2x80x9d) will act initially via coagulation. However, these mechanisms will have some cross-over, as cell destruction exposes basement membranes and results in coagulation, and as coagulation deprives the cells of oxygen and nutrients and results in cell destruction.
Naked or unconjugated antibodies against aminophospholipid components are also capable of specifically inducing tumor blood vessel destruction and tumor necrosis in vivo. Such methods of tumor treatment are also contemplated by the present inventors, and are disclosed and claimed in first and second provisional applications Serial Nos. 60/092,672 (filed Jul. 13, 1998) and 60/110,608 (filed Dec. 02, 1998) and in co-filed U.S. and PCT patent applications U.S. application Ser. No. 09/351,543, now U.S. Pat. No. 6,406,693, U.S. application Ser. No. 09/351,862, now pending and PCT/US99/15,600 published as, each WO 00/02584 specifically incorporated herein by reference. In light of the beneficial effects of naked anti-aminophospholipid antibodies, the mechanism of action of the present conjugates may extend beyond the mode of action of the particular therapeutic agent or agents employed.
Therefore, the following mechanisms may contribute to the success of the invention: cell-mediated cytotoxicity, complement-mediated lysis, apoptosis, antibody-induced cell signaling (direct signaling), or mimicking or altering signal transduction pathways (indirect signaling).
The treatment methods thus include administering to an animal or patient having a vascularized tumor at least a first pharmaceutical composition comprising an amount of at least a first therapeutic agent-targeting agent construct effective to induce, or specifically induce, cell-mediated cytotoxicity of at least a portion of the tumor or intratumoral vascular endothelial cells. Herein, the first therapeutic agent-targeting agent construct binds to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, present, expressed, translocated, presented or complexed at the luminal surface of tumor or intratumoral vascular endothelial cells and induces cell-mediated cytotoxicity of at least a portion of the tumor or intratumoral vascular endothelial cells, as opposed to endothelial cells in normal vessels. As used herein, xe2x80x9ccell-mediated cytotoxicity or destructionxe2x80x9d includes ADCC (antibody-dependent, cell-mediated cytotoxicity) and NK (natural killer) cell killing.
The methods further include administering to an animal or patient having a vascularized tumor at least a first pharmaceutical composition comprising an amount of at least a first therapeutic agent-targeting agent construct effective to induce, or specifically induce, complement-mediated lysis of at least a portion of the tumor or intratumoral vascular endothelial cells. Herein, the first therapeutic agent-targetingagent construct binds to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, present, expressed, translocated, presented or complexed at the luminal surface of tumor or intratumoral vascular endothelial cells and induces complement-mediated lysis of at least a portion of the tumor or intratumoral vascular endothelial cells, as opposed to endothelial cells in normal vessels.
As used herein, xe2x80x9ccomplement-mediated or complement-dependent lysis or cytotoxicityxe2x80x9d means the process by which the complement-dependent coagulation cascade is activated, multi-component complexes are assembled, ultimately generating a lytic complex that has direct lytic action, causing cell permeabilization. Therapeutic agent-targeting agents for use in inducing complement-mediated lysis will generally include an antibody Fc portion.
The complement-based mechanisms by which the present invention may operate further include xe2x80x9ccomplement-activated ADCCxe2x80x9d. In such aspects, the administered therapeutic agent-targeting agent contains an antibody, or fragment thereof, that binds to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, present, expressed, translocated, presented or complexed at the luminal surface of tumor or intratumoral vascular endothelial cells and induces complement-activated ADCC of at least a portion of the tumor or intratumoral vascular endothelial cells, as opposed to endothelial cells in normal vessels. xe2x80x9cComplement-activated ADCCxe2x80x9d is used to refer to the process by which complement, not an antibody Fc portion per se, holds a multi-component complex together and in which cells such as neutrophils lyse the target cell.
In other embodiments, the methods include administering to an animal or patient having a vascularized tumor at least a first pharmaceutical composition comprising an amount of at least a first therapeutic agent-targeting agent construct effective to induce, or specifically induce, apoptosis in at least a portion of the tumor or intratumoral vascular endothelial cells. Herein, the first therapeutic agent-targeting agent construct binds to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, present, expressed, translocated, presented or complexed at the luminal surface of tumor or intratumoral vascular endothelial cells and induces apoptosis in least a portion of the tumor or intratumoral vascular endothelial cells, as opposed to endothelial cells in normal vessels.
As used herein, xe2x80x9cinduces apoptosisxe2x80x9d means induces the process of programmed cell death that, during the initial stages, maintains the integrity of the cell membrane, yet transmits the death-inducing signals into the cell. This is opposed to the mechanisms of cell necrosis, during which the cell membrane loses its integrity and becomes leaky at the onset of the process.
Therapeutic benefits may be realized by the administration of at least two, three or more therapeutic agent-targeting agent constructs. The therapeutic agent-targeting agent constructs may also be combined with other therapies to provide combined therapeutically effective amounts, as disclosed herein.
The treatment methods of the present invention will generally involve the administration of the pharmaceutically effective composition to the animal systemically, such as via intravenous injection. However, any route of administration that allows the therapeutic agent-targeting agent construct to localize to the tumor or intratumoral vascular endothelial cells will be acceptable.
xe2x80x9cAdministrationxe2x80x9d, as used herein, therefore means provision or delivery of therapeutic agent-targeting agent constructs in an amount(s) and for a period of time(s) effective to allow binding to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, present, expressed, translocated, presented or complexed at the luminal surface of blood transporting vessels of the vascularized tumor, and to exert a tumor vasculature destructive and tumor-regressive effect. The passive administration of proteinaceous therapeutic agent-targeting agent constructs is generally preferred, in part, for its simplicity and reproducibility.
However, the term xe2x80x9cadministrationxe2x80x9d is herein used to refer to any and all means by which therapeutic agent-targeting agent constructs are delivered or otherwise provided to the tumor vasculature. xe2x80x9cAdministrationxe2x80x9d therefore includes the provision of cells that produce the therapeutic agent-targeting agent constructs in a manner effective to result in the delivery of the therapeutic agent-targeting agent constructs to the tumor vasculature, and/or their localization to such vasculature. In such embodiments, it may be desirable to formulate or package the cells in a selectively permeable membrane, structure or implantable device, generally one that can be removed to cease therapy. Exogenous therapeutic agent-targeting agent administration will still generally be preferred, as this represents a non-invasive method that allows the dose to be closely monitored and control led.
The xe2x80x9ctherapeutic agent-targeting agent administration methodsxe2x80x9d of the invention also extend to the provision of nucleic acids that encode therapeutic agent-targeting agent constructs in a manner effective to result in the expression of the therapeutic agent-targeting agent constructs in the vicinity of the tumor vasculature, and/or in the expression of therapeutic agent-targeting agent constructs that can localize to the tumor vasculature. Any gene therapy technique may be employed, such as naked DNA delivery, recombinant genes and vectors, cell-based delivery, including ex vivo manipulation of patients"" cells, and the like.
One of the benefits of the present invention is that aminophospholipids, particularly phosphatidylserine and phosphatidylethanolamine, are generally expressed or available throughout the tumor vessels. Aminophospholipid expression on established, intratumoral blood vessels is advantageous as targeting and destroying such vessels will rapidly lead to anti-tumor effects. However, so long as the administered therapeutic agent-targeting agent constructs bind to at least a portion of the blood transporting vessels, significant anti-tumor effects will ensue. This will not be problematical as aminophospholipids, such as phosphatidylserine and phosphatidylethanolamine, are expressed on the large, central vessels, and also on veins, venules, arteries, arterioles and blood transporting capillaries in all regions of the tumor.
In any event, the ability of the therapeutic agent-targeting agent constructs to destroy the tumor vasculature means that tumor regression can be achieved, rather than only tumor stasis. Tumor stasis is most often the result of anti-angiogenic therapies that target only the budding vessels at the periphery of a solid tumor and stop the vessels proliferating. Even if the present invention targeted more of the peripheral regions of the tumor in certain tumor types, which is not currently believed to be the case, destruction of the blood transporting vessels in such areas would still lead to widespread thrombosis and tumor necrosis.
The targeting portions of the diagnostic and/or therapeutic agent-targeting agent constructs of the present invention, whether binding to phosphatidylethanolamineor phosphatidylserine, may be either antibody-based or binding ligand or binding protein based. Any aminophospholipid binding ligand or protein known in the art may thus now be advantageously used in the delivery of therapeutic agents to tumor vasculature.
By way of example only, suitable aminophospholipid binding ligands and proteins include low and high molecular weight kininogens and other rat, bovine, monkey or human phosphatidylethanolamine binding proteins; and any one or more of a number of phosphatidylserine-serine binding annexins. The protein and DNA sequences for such binding ligands are known in the art and incorporated herein by reference, facilitating the production of recombinant fusion proteins for use in the present invention.
Aminophospholipid binding reagents encompassed by the term xe2x80x9caminophospholipid binding ligands or binding proteinsxe2x80x9d extend to all aminophospholipid binding ligands and proteins from all species, and aminophospholipid binding fragments thereof, including dimeric, trimeric and multimeric ligands and proteins; bispecific ligands and proteins; chimeric ligands and proteins; human ligands and proteins; recombinant and engineered ligands and proteins, and fragments thereof.
Where antibody-based targeting portions are employed, whether binding to phosphatidylethanolamineor phosphatidylserine, the term xe2x80x9canti-aminophospholipid antibodyxe2x80x9d, as used herein, refers broadly to any immunologic binding agent, such as polyclonal and monoclonal IgG, IgM, IgA, IgD and IgE antibodies. Generally, IgG and/or IgM are preferred because they are the most common antibodies in the physiological situation and because they are most easily made in a laboratory setting.
Polyclonal anti-aminophospholipid antibodies, obtained from antisera, may be employed in the invention. However, the use of monoclonal anti-aminophospholipid antibodies (MAbs) will generally be preferred. MAbs are recognized to have certain advantages, e.g., reproducibility and large-scale production, that makes them suitable for clinical treatment. The invention thus provides monoclonal antibodies of the murine, human, monkey, rat, hamster, rabbit and even frog or chicken origin. Due to the ease of preparation and ready availability of reagents, murine monoclonal antibodies will be used in certain embodiments.
As will be understood by those in the art, the immunologic binding reagents encompassed by the term xe2x80x9canti-aminophospholipid antibodyxe2x80x9d extend to all anti-aminophospholipid antibodies from all species, and antigen binding fragments thereof, including dimeric, trimeric and multimeric antibodies; bispecific antibodies; chimeric antibodies; human and humanized antibodies; recombinant and engineered antibodies, and fragments thereof.
The term xe2x80x9canti-aminophospholipid antibodyxe2x80x9d is thus used to refer to any anti-aminophospholipid antibody-like molecule that has an antigen binding region, and includes antibody fragments such as Fabxe2x80x2, Fab, F(abxe2x80x2)2, single domain antibodies (DABs), Fv, scFv (single chain Fv), and the like. The techniques for preparing and using various antibody-based constructs and fragments are well known in the art.
In certain embodiments, the antibodies employed in the therapeutic agent-targeting agent constructs will be xe2x80x9chumanizedxe2x80x9d or human antibodies. xe2x80x9cHumanizedxe2x80x9d antibodies are generally chimeric monoclonal antibodies from mouse, rat, or other non-human species, bearing human constant and/or variable region domains (xe2x80x9cpart-human chimeric antibodiesxe2x80x9d). Mostly, humanized monoclonal antibodies for use in the present invention will be chimeric antibodies wherein at least a first antigen binding region, or complementarity determining region (CDR), of a mouse, rat or other non-human anti-aminophospholipid monoclonal antibody is operatively attached to, or xe2x80x9cgraftedxe2x80x9d onto, a human antibody constant region or xe2x80x9cframeworkxe2x80x9d.
xe2x80x9cHumanizedxe2x80x9d monoclonal antibodies for use herein may also be anti-aminophospholipid monoclonal antibodies from non-human species wherein one or more selected amino acids have been exchanged for amino acids more commonly observed in human antibodies. This can be readily achieved through the use of routine recombinant technology, particularly site-specific mutagenesis.
Entirely human, rather than xe2x80x9chumanizedxe2x80x9d, anti-aminophospholipid antibodies may also be prepared and used in the therapeutic agent-targeting agent constructs of the present invention. Such human antibodies may be polyclonal antibodies, as obtained from human patients that have any one or more of a variety of diseases, disorders or clinical conditions associated with the production of anti-aminophospholipid antibodies. Such antibodies may be concentrated, partially purified or substantially purified for use herein.
A range of techniques are also available for preparing human monoclonal antibodies. As human patients with anti-aminophospholipid antibody-producing diseases exist, the anti-aminophospholipid antibody-producing cells from such patients may be obtained and manipulated in vitro to provide a human monoclonal antibody for use in a therapeutic agent-targeting agent constrict. The in vitro manipulations or techniques include fusing to prepare a monoclonal antibody-producing hybridoma, and/or cloning the gene(s) encoding the anti-aminophospholipid antibody from the cells (xe2x80x9crecombinanthuman antibodiesxe2x80x9d).
Human anti-aminophospholipid antibody-producing cells may also be obtained from human subjects without an anti-aminophospholipid antibody-associated disease, i.e. xe2x80x9chealthy subjectsxe2x80x9d in the context of the present invention. To achieve this, one would simply obtain a population of mixed peripheral blood lymphocytes from a human subject, including antigen-presenting and antibody-producing cells, and stimulate the cell population in vitro by admixing with an immunogenically effective amount of an aminophospholipid sample. Again, the human anti-aminophospholipid antibody-producing cells, once obtained, could be used in hybridoma and/or recombinant antibody production prior to therapeutic agent-targeting agent construct preparation.
Further techniques for human monoclonal antibody production include immunizing a transgenic animal, preferably a transgenic mouse, that comprises a human antibody library with an immunogenically effective amount of an aminophospholipid sample. This also generates human anti-aminophospholipid antibody-producing cells for further manipulation in hybridoma and/or recombinant antibody production, with the advantage that spleen cells, rather than peripheral blood cells, can be readily obtained from the transgenic animal or mouse.
Preferred anti-aminophospholipid antibodies for use in the therapeutic agent-targeting agent constructs of the present invention are anti-phosphatidylserine (anti-PS) and anti-phosphatidylethanolamine (anti-PE) antibodies. Anti-PS antibodies will generally recognize, bind to or have immunospecificity for the PS molecule present, expressed, translocated, presented or complexed at the luminal surface of tumor vascular endothelial cells. Suitable antibodies will thus bind to phosphatidyl-L-serine (Umeda et al., 1989; incorporated herein by reference). Anti-PE antibodies will generally recognize, bind to or have immunospecificity for the PE molecule present, expressed, translocated, presented or complexed at the luminal surface of tumor vascular endothelial cells.
Administering diagnostic and/or therapeutic agent-targeting agent constructs to an animal with a tumor will result in specific binding to the aminophospholipid molecules present, expressed or translocated to the luminal surface of the tumor blood vessels, i.e., the therapeutic agent-targeting agent constructs will bind to the aminophospholipid molecules in a natural, biological environment. Therefore, no particular manipulation will be necessary to ensure binding.
However, in terms of antibody binding, it is of scientific interest to note that aminophospholipids may be most frequently recognized, or bound, by anti-aminophospholipid antibodies when the aminophospholipid molecules are associated with one or more proteins or other non-lipid biological components. For example, anti-PS antibodies that occur as a sub-set of anti-phospholipid (anti-PL) antibodies in patients with certain diseases and disorders are now believed to bind to PS in combination with proteins such as xcex22-glycoprotein I (xcex22-GPI or apolipoprotein H, apoh) and prothrombin (U.S. Pat. No. 5,344,758; Rote, 1996; each incorporated herein by reference). Similarly, anti-PE antibodies that occur in disease states are now believed to bind to PE in combination with proteins such as low and high molecular weight kininogen (HK), prekallikrein and even factor XI (Sugi and McIntyre, 1995; 1996a; 1996b; each incorporated herein by reference).
This is the meaning of the terms xe2x80x9cpresentedxe2x80x9d and xe2x80x9ccomplexed atxe2x80x9d the luminal surface of tumor blood vessels, as used herein, which mean that the aminophospholipid molecules are present at the surface of tumor blood vessels in a binding competent state, or antibody-binding competent state, irrespective of the molecular definition of that particular state. PS may even be targeted as a complex with factor II/IIa, VII/VIIa, IX/IXa and X/Xa. Moreover, the nature of the aminophospholipid target may change during practice of the invention, as the initial aminophospholipid antibody binding, anti-endothelial cell and anti-tumor effects may result in biological changes that alter the number, conformation and/or type of the aminophospholipid target epitope(s).
The term xe2x80x9canti-aminophospholipid antibodyxe2x80x9d, as used in the context of the present invention, therefore means any antibody, immunological binding agent or antisera; monoclonal, human, humanized, dimeric, trimeric, multimeric, chimeric, bispecific, recombinant or engineered antibody; or Fabxe2x80x2, Fab, F(abxe2x80x2)2, DABs, Fv or scFv antigen binding fragment thereof; that at least binds to a lipid and amino group-containing complex or aminophospholipid target, preferably a phosphatidylserine- or phosphatidylethanolamine-based target.
The requirement that the antibody xe2x80x9cat least bind to an aminophospholipid targetxe2x80x9d is met by the antibody binding to any and/or all physiologically relevant forms of aminophospholipids, including so-called xe2x80x9chexagonalxe2x80x9d and xe2x80x9chexagonal phase IIxe2x80x9d PS and PE (HexII PS and HexII PE) (Rauch et al., 1986; Rauch and Janoff, 1990; Berard et al., 1993; each incorporated herein by reference) and PS and PE in combination with any other protein, lipid, membrane component, plasma or serum component, or any combination thereof. Thus, an xe2x80x9canti-aminophospholipid antibodyxe2x80x9d is an antibody that binds to an aminophospholipid in the tumor blood vessels, notwithstanding the fact that bilayer or micelle aminophospholipids may be considered to be immunogenically neutral.
The anti-aminophospholipid antibodies may recognize, bind to or have immunospecificity for aminophospholipid molecules, or an immunogenic complex thereof (including hexagonal aminophospholipids and protein combinations), to the exclusion of other phospholipids or lipids. Such antibodies may be termed xe2x80x9carninophospholipid-specific or aminophospholipid-restricted antibodiesxe2x80x9d, and their use in the therapeutic agent-targeting agent constructs of the invention will often be preferred. xe2x80x9cAminophospholipid-specific or aminophospholipid-restricted antibodiesxe2x80x9d will generally exhibit significant binding to aminophospholipids, while exhibiting little or no significant binding to other lipid components, such as phosphatidylinositol (PI), phosphatidylglycerol (PG) and even phosphatidylcholine (PC) in certain embodiments.
xe2x80x9cPS-specific or PS-restricted antibodiesxe2x80x9d will generally exhibit significant binding to PS, while exhibiting little or no significant binding to lipid components such as phosphatidylethanolamine and cardiolipin (CL), as well as PC, PI and PG. xe2x80x9cPE-specific or PE-restricted antibodiesxe2x80x9d will generally exhibit significant binding to PE, while exhibiting little or no significant binding to lipid components such as phosphatidylserine and cardiolipin, as well as PC, PI and PG. The preparation of specific anti-aminophospholipid antibodies is readily achieved, e.g., as disclosed by Rauch et al. (1986); Umeda et al. (1989); Rauch and Janoff (1990); and Rote et al. (1993); each incorporated herein by reference. xe2x80x9cCross-reactive anti-aminophospholipid antibodiesxe2x80x9d that recognize, bind to or have immunospecificity for an aminophospholipid molecule, or an immunogenic complex thereof (including hexagonal aminophospholipids and protein combinations), in addition to exhibiting lesser but detectable binding to other phospholipid or lipid components are by no means excluded from use in the invention. Such xe2x80x9ccross-reactive anti-aminophospholipid antibodiesxe2x80x9d may be employed so long as they bind to an aminophospholipid present, expressed, translocated, presented or complexed at the luminal surface of tumor vascular endothelial cells in vivo.
Further suitable aninophospholipid-specific or aminophospholipid-restricted antibodies are those anti-aminophospholipid antibodies that bind to both PS and PE. While clearly being specific or restricted to aminophospholipids, as opposed to other lipid components, antibodies exist that bind to each of the preferred targets of the present invention. Examples of such antibodies for use in the therapeutic agent-targeting agent constructs of the invention include, but are not limited to, PS3A, PSF6, PSF7, PSB4, PS3H1 and PS3E10 (Igarashi et al., 1991; incorporated herein by reference)
Further exemplary anti-PS antibodies for use in the therapeutic agent-targeting agent constructs include, but are not limited to BA3B5C4, PS4A7, PS1G3 and 3SB9b; with PS4A7, PS1G3 and 3SB9b generally being preferred. Monoclonal antibodies, humanized antibodies and/or antigen-binding fragments based upon the 3SB9b antibody (Rote et al., 1993; incorporated herein by reference) are currently most preferred.
Although aminophospholipids, such as PS and PE, in bilayer or micelle form have been reported to be non- or weakly antigenic, or non- or weakly-immunogenic, the scientific literature has reported no difficulties in generating anti-aminophospholipid antibodies, such as anti-PS and anti-PE antibodies. Anti-aminophospholipid antibodies or monoclonal antibodies may therefore be readily prepared by preparative processes and methods that comprise:
(a) preparing an anti-aminophospholipidantibody-producingcell; and
(b) obtaining an anti-aminophospholipid antibody or monoclonal antibody from the antibody-producingcell.
The processes of preparing anti-aminophospholipidantibody-producingcells and obtaining anti-aminophospholipidantibodies therefrom may be conduced in situ in a given patient. That is, simply providing an immunogenically effective amount of an immunogenic aminophospholipid sample to a patient will result in anti-aminophospholipid antibody generation. Thus, the anti-aminophospholipid antibody is still xe2x80x9cobtainedxe2x80x9d from the antibody-producing cell, but it does not have to be isolated away from a host and subsequently provided to a patient, being able to spontaneously localize to the tumor vasculature and exert its biological anti-tumor effects.
As disclosed herein, anti-aminophospholipid antibody-producing cells may be obtained, and antibodies subsequently isolated and/or purified, from human patients with anti-aminophospholipid antibody-producing diseases, from stimulating peripheral blood lymphocytes with aminophospholipidsin vitro, and also by immunization processes and methods. The latter of which generally comprise:
(a) immunizing an animal by administering to the animal at least one dose, and optionally more than one dose, of an immunogenically effective amount of an immunogenic aminophospholipid sample (such as a hexagonal, or hexagonal phase II form of an aminophospholipid), preferably an immunogenic PS or PE sample; and
(b) obtaining an anti-aminophospholipid antibody-producing cell from the immunized animal.
The immunogenically effective amount of the aminophospholipidsample or samples may be a Salmonella-coated aminophospholipid sample (Umeda et al., 1989; incorporated herein by reference); an aminophospholipid micelle, liposome, lipid complex or lipid formulation sample; or an aminophospholipidsample fabricated with SDS. Any such aminophospholipidsample may be administered in combination with any suitable adjuvant, such as Freund""s complete adjuvant (Rote et al., 1993; incorporated herein by reference). Any empirical technique or variation may be employed to increase immunogenicity, and/or hexagonal or hexagonal phase II forms of the aminophospholipids may be administered.
The immunization may be based upon one or more intrasplenic injections of an immunogenically effective amount of an aminophospholipid sample (Umeda et al., 1989; incorporated herein by reference).
Irrespective of the nature of the immunization process, or the type of immunized animal, anti-aminophospholipid antibody-producing cells are obtained from the immunized animal and, preferably, further manipulated by the hand of man. xe2x80x9cAn immunized animalxe2x80x9d, as used herein, is a non-human animal, unless otherwise expressly stated. Although any antibody-producing cell may be used, most preferably, spleen cells are obtained as the source of the antibody-producing cells. The anti-aminophospholipid antibody-producing cells may be used in a preparative process that comprises:
(a) fusing an anti-aminophospholipidantibody-producingcell with an immortal cell to prepare a hybridoma that produces an anti-aminophospholipidmonoclonal antibody and
(b) obtaining an anti-aminophospholipidmonoclonal antibody from the hybridoma.
Hybridoma-based monoclonal antibody preparative methods thus include those that comprise:
(a) immunizing an animal by administering to the animal at least one dose, and optionally more than one dose, of an immunogenically effective amount of an immunogenic aminophospholipid sample (such as a hexagonal, or hexagonal phase II form of an aminophospholipid), preferably an immunogenic PS or PE sample;
(b) preparing a collection of monoclonal antibody-producing hybridomas from the immunized animal;
(c) selecting from the collection at least a first hybridoma that produces at least a first anti-aminophospholipid monoclonal antibody, and preferably, at least a first aminophospholipid-specific monoclonal antibody; and
(d) culturing the at least a first anti-aminophospholipid-producing or aminophospholipid-specific hybridoma to provide the at least a first anti-aminophospholipid monoclonal antibody or aminophospholipid-specific monoclonal antibody; and preferably
(e) obtaining the at least a first anti-aminophospholipid monoclonal antibody or aminophospholipid-specific monoclonal antibody from the cultured at least a first hybridoma.
As non-human animals are used for immunization, the anti-aminophospholipid monoclonal antibodies obtained from such a hybridoma will often have a non-human make up. Such antibodies may be optionally subjected to a humanization process, grafting or mutation, as known to those of skill in the art and further disclosed herein. Alternatively, transgenic animals, such as mice, may be used that comprise a human antibody gene library. Immunization of such animals will therefore directly result in the generation of human anti-aminophospholipid antibodies.
After the production of a suitable antibody-producing cell, most preferably a hybridoma, whether producing human or non-human antibodies, the monoclonal antibody-encoding nucleic acids may be cloned to prepare a xe2x80x9crecombinantxe2x80x9d monoclonal antibody. Any recombinant cloning technique may be utilized, including the use of PCR to prime the synthesis of the antibody-encoding nucleic acid sequences. Therefore, yet further appropriate monoclonal antibody preparative methods include those that comprise using the anti-aminophospholipid antibody-producing cells as follows:
(a) obtaining at least a first anti-aminophospholipid antibody-encoding nucleic acid molecule or segment from an anti-aminophospholipid antibody-producing cell, preferably a hybridoma; and
(b) expressing the nucleic acid molecule or segment in a recombinant host cell to obtain a recombinant anti-aminophospholipidmonoclonal antibody.
However, other powerful recombinant techniques are available that are ideally suited to the preparation of recombinant monoclonal antibodies. Such recombinant techniques include the phagemid library-based monoclonal antibody preparative methods comprising:
(a) immunizing an animal by administering to the animal at least one dose, and optionally more than one dose, of an immunogenically effective amount of an immunogenic aminophospholipid sample (such as a hexagonal, or hexagonal phase II form of an aminophospholipid), preferably an immunogenic PS or PE sample;
(b) preparing a combinatorial immunoglobulin phagemid library expressing RNA isolated from the antibody-producing cells, preferably from the spleen, of the immunized animal;
(c) selecting from the phagemid library at least a first clone that expresses at least a first anti-aminophospholipid antibody, and preferably, at least a first aminophospholipid-specific antibody;
(d) obtaining anti-aminophospholipidantibody-encodingnucleic acids from the at least a first selected clone and expressing the nucleic acids in a recombinant host cell to provide the at least a first anti-aminophospholipid antibody or aminophospholipid-specific antibody; and preferably
(e) obtaining the at least a first anti-aminophospholipid antibody or aminophospholipid-specific antibody expressed by the nucleic acids obtained from the at least a first selected clone.
Again, in such phagemid library-based techniques, transgenic animals bearing human antibody gene libraries may be employed, thus yielding recombinant human monoclonal antibodies.
Irrespective of the manner of preparation of a first anti-aminophospholipid antibody nucleic acid segment, further suitable anti-aminophospholipid antibody nucleic acid segments may be readily prepared by standard molecular biological techniques. In order to confirm that any variant, mutant or second generation anti-aminophospholipid antibody nucleic acid segment is suitable for use in the present invention, the nucleic acid segment will be tested to confirm expression of an antibody that binds to an aminophospholipid. Preferably, the variant, mutant or second generation anti-aminophospholipid antibody nucleic acid segment will also be tested to confirm hybridization to an anti-aminophospholipid antibody nucleic acid segment under standard, more preferably, standard stringent hybridization conditions. Exemplary suitable hybridization conditions include hybridization in about 7% sodium dodecyl sulfate (SDS), about 0.5 M NaPO4, about 1 mM EDTA at about 50xc2x0 C.; and washing with about 1% SDS at about 42xc2x0 C.
As a variety of recombinant monoclonal antibodies, whether human or non-human in origin, may be readily prepared, the treatment methods of the invention may be executed by providing to the animal or patient at least a first nucleic acid segment that expresses a biologically effective amount of at least a first therapeutic agent-targeting agent construct in the patient. The xe2x80x9cnucleic acid segment that expresses a therapeutic agent-targeting agent constructxe2x80x9d will generally be in the form of at least an expression construct, and may be in the form of an expression construct comprised within a virus or within a recombinant host cell. Preferred gene therapy vectors of the present invention will generally be viral vectors, such as comprised within a recombinant retrovirus, herpes simplex virus (HSV), adenovirus, adeno-associated virus (AAV), cytomegalovirus (CMV), and the like.
Once a targeting agent has been selected, whether antibody-based or binding ligand-based, and whether binding to phosphatidylethanolamineand/or phosphatidylserine, the targeting agent is operatively attached to one or more diagnostic and/or therapeutic agents or xe2x80x9ceffectorxe2x80x9d portions. The therapeutic agents of the present constructs will generally be either anti-cellular, cytotoxic or anti-angiogenic agents, or coagulation factors (coagulants).
The use of anti-cellular, cytotoxic and/or anti-angiogenic agents results in xe2x80x9caminophospholipid immunotoxinsxe2x80x9d (or anti-aminophospholipid immunotoxins), whereas the use of coagulation factors results in xe2x80x9caminophospholipid coaguligandsxe2x80x9d (or anti-aminophospholipid coaguligands). These terms are again used for simplicity and succinctly refer to aminophospholipid binding ligands or therapeutic agent-aminophospholipid targeting agent constructs in terms of their attached therapeutic moiety.
The present invention further provides binding ligands, and methods of use, comprising at least two therapeutic agents operatively attached to a targeting agent comprising a single aminophospholipid binding site. The binding ligands may comprise at least two therapeutic agents operatively attached to a targeting agent that comprises at least two aminophospholipid binding sites; or a plurality of therapeutic agents operatively attached to a targeting agent that comprises a plurality of aminophospholipid binding sites, generally at regions distinct from the aminophospholipid binding sites.
Combinations of anti-cellular and cytotoxic agents with coagulation factors are also contemplated, irrespective of the number of aminophospholipid binding sites. The combined use of therapeutic agents of different classes, such as cytotoxins and coagulants, is also contemplated in embodiments where two or more binding ligands are administered t o the animal, each containing a single type of therapeuticagent. Different cytotoxins may also be employed in one or more binding ligands or methods, such as DNA synthesis inhibitors combined with classic cytotoxins, such as ricin.
In certain applications, the aminophospholipid-targeted constructs will be operatively attached to cytotoxic, cytostatic or otherwise anti-cellular agents that have the ability to kill or suppress the growth or cell division of endothelial cells. Suitable anti-cellular agents include chemotherapeutic agents, as well as cytotoxins and cytostatic agents. Cytostatic agents are generally those that disturb the natural cell cycle of a target cell, preferably so that the cell is taken out of the cell cycle.
Exemplary chemotherapeutic agents include: steroids; cytokines; anti-metabolites, such as cytosine arabinoside, fuorouracil, methotrexate or aminopterin; anthracyclines; mitomycin C; vinca alkaloids; antibiotics; demecolcine; etoposide; mithramycin; and anti-tumor alkylating agents, such as chlorambucil or melphalan. Indeed, any of the agents disclosed herein in Table C could be used. Certain preferred anti-cellular agents are DNA synthesis inhibitors, such as daunorubicin, doxorubicin, adriamycin, and the like.
In other embodiments, aminophospholipid-targeted constructs of the invention may be operatively attached to anti-angiogenic agents that, acting either alone or in concert with other host factors, or administered therapeutic agents, have the ability to prevent or inhibit vascularization and/or to induce regression of blood vessels. Suitable anti-angiogenic agents include those listed in Table D, as well as other anti-angiogenric agents known to those of skill in the art. By way of example only, one may mention the angiopoietins, preferably, angiopoietin-2 (Ang-2; SEQ ID NO:3 and SEQ ID NO:4), but also angiopoietin-1 (Ang-1; SEQ ID NO:1 and SEQ ID NO:2), angiopoietin fusion proteins (for example, as in SEQ ID NO:5), and even angiopoietin-3 and angiopoietin-4.
In certain therapeutic applications, toxin moieties will be preferred, due to the much greater ability of most toxins to deliver a cell killing effect, as compared to other potential agents. Therefore, certain preferred anti-cellular agents for aminophospholipid-targeted constructs are plant-, fungus- or bacteria-derived toxins. Exemplary toxins include epipodophyllotoxins; bacterial endotoxin or the lipid A moiety of bacterial endotoxin; ribosome inactivating proteins, such as saporin or gelonin; xcex1-sarcin; aspergillin; restrictocin; ribonucleases, such as placental ribonuclease; diphtheria toxin and pseudomonas exotoxin.
Preferred toxins for certain embodiments are gelonin and/or the A chain toxins, such as ricin A chain. The most preferred toxin moiety is often ricin A chain that has been treated to modify or remove carbohydrate residues, so called xe2x80x9cdeglycosylated A chainxe2x80x9d (dgA). Deglycosylated ricin A chain is preferred because of its extreme potency, longer half-life, and because it is economically feasible to manufacture it a clinical grade and scale. Recombinant and/or truncated ricin A chain may also be used.
For tumor targeting and treatment with immunotoxins, the following patents and patent applications are specifically incorporated herein by reference for the purposes of even further supplementing the present teachings regarding anticellular and cytotoxic agents: U.S. Pat. Nos. 5,855,866; 5,776,427; 5,863,538; and 5,660,827; and U.S. applications Ser. No. 07/846,349; 08/295,868 (U.S. Pat. No. 5,965,132; Issue Fee paid); U.S. Ser. No. 08/350,212 (U.S. Pat. No. 5,051,230; Issue Fee paid); and U.S. Ser. No. 08/457,869 (Notice of Allowance Received).
The aminophospholipid-targeted constructs of the invention may comprise a component that is capable of promoting coagulation, i.e., a coagulant. Here, the targeting antibody or ligand may be directly or indirectly, e.g., via another antibody, linked to a factor that directly or indirectly stimulates coagulation.
Preferred coagulation factors for such uses are Tissue Factor (TF) and TF derivatives, such as truncated TF (tTF), dimeric, trimeric, polymeric/multimeric TF, and mutant TF deficient in the ability to activate Factor VII. Other suitable coagulation factors include vitamin K-dependent coagulants, such as Factor II/IIa, Factor VII/VIIa, Factor IX/IXa and Factor X/Xa; vitamin K-dependent coagulation factors that lack the Gla modification; Russell""s viper venom Factor X activator; platelet-activating compounds, such as thromboxane A2 and thromboxane A2 synthase; and inhibitors of fibrinolysis, such as xcex12-antiplasmin.
Tumor targeting and treatment with coaguligands is described in the following patents and patent applications, each of which are specifically incorporated herein by reference for the purposes of even further supplementing the present teachings regarding coaguligands and coagulation factors: U.S. Pat. Nos. 5,855,866 and 5,877,289; U.S. applications Ser. Nos. 07/846,349; 08/350,212 (U.S. Pat. No. 5,965,132; Issue Fee paid); U.S. Ser. No. 08/482,369 (U.S. Pat. 6,093,399, Issue Fee paid); U.S. Ser. No. 08/487,427 (U.S. Pat. 6,004,555; Issue Fee paid); and U.S. Ser. No 08/479,727 (U.S. Pat. No. 036,955; Issue Fee paid).
As somewhat wider distribution of a coagulating agent will not be associated with severe side effects, there is a less stringent requirement imposed on the targeting element of coaguligands than with immunotoxins. Therefore, to achieve specific targeting means that coagulation is promoted in the tumor vasculature relative to the vasculature in non-tumor sites. Thus, specific targeting of a coaguligand is a functional term, rather than a purely physical term relating to the biodistribution properties of the targeting agent.
The preparation of immunotoxins is generally well known in the art (see, e.g., U.S. Pat. No. 4,340,535, incorporated herein by reference). Each of the following patents and patent applications are further incorporated herein by reference for the purposes of even further supplementing the present teachings regarding immunotoxin generation, purification and use: U.S. Pat. Nos. 5,855,866; 5,776,427; 5,863,538; and 5,660,827; and U.S. applications Ser. No. 07/846,349; 08/295,868 (U.S. Pat. No. Issue Fee paid); U.S. Ser. No. 08/350,212 (U.S. Pat. No. 5,965,132; Issue Fee paid); and U.S. Ser. No. 08/457,869 (Notice of Allowance Received).
In the preparation of immunotoxins, advantages may be achieved through the use of certain linkers. For example, linkers that contain a disulfide bond that is sterically xe2x80x9chinderedxe2x80x9d are often preferred, due to their greater stability in vivo, thus preventing release of the toxin moiety prior to binding at the site of action. It is generally desired to have a conjugate that will remain intact under conditions found everywhere in the body except the intended site of action, at which point it is desirable that the conjugate have good xe2x80x9creleasexe2x80x9d characteristics.
Depending on the specific toxin compound used, it may be necessary to provide a peptide spacer operatively attaching the targeting agent and the toxin compound, wherein the peptide spacer is capable of folding into a disulfide-bonded loop structure. Proteolytic cleavage within the loop would then yield a heterodimeric polypeptide wherein the targeting agent and the toxin compound are linked by only a single disulfide bond.
When certain other toxin compounds are utilized, a non-cleavable peptide spacer may be provided to operatively attach the targeting agent and the toxin compound. Toxins that may be used in conjunction with non-cleavable peptide spacers are those that may, themselves, be converted by proteolytic cleavage, into a cytotoxic disulfide-bonded form. An example of such a toxin compound is a Pseudonomas exotoxin compound.
A variety of chemotherapeutic and other pharmacological agents can also be successfully conjugated to aminophospholipid antibodies or targeting ligands. Exemplary antineoplastic agents that have been conjugated to antibodies include doxorubicin, daunomycin, methotrexate and vinblastine. Moreover, the attachment of other agents such as neocarzinostatin, macromycin, trenimon and xcex1-amanitin has been described (see U.S. Pat. No. 5,855,866; and U.S. Pat. No. 5,965,132 (application Ser. No. 08/350,212, Issue Fee paid) and references incorporated therein.
In light of one of the present inventors earlier work, the preparation of coaguligands is now also easily practiced. The operable association of one or more coagulation factors with an aminophospholipid targeting agent may be a direct linkage, such as those described above for the immunotoxins. Alternatively, the operative association may be an indirect attachment, such as where the targeting agent is operatively attached to a second binding region, preferably and antibody or antigen binding region of an antibody, that binds to the coagulation factor. The coagulation factor should be attached to the targeting agent at a site distinct from its functional coagulating site, particularly where a covalent linkage is used to join the molecules.
Indirectly linked coaguligands are often based upon bispecific antibodies. The preparation of bispecific antibodies is also well known in the art. One preparative method involves the separate preparation of antibodies having specificity for the targeted tumor component, on the one hand, and the coagulating agent on the other. Peptic F(abxe2x80x2xcex3)2 fragments from the two chosen antibodies are then generated, followed by reduction of each to provide separate Fabxe2x80x2ysH fragments. The SH groups on one of the two partners to be coupled are then alkylated with a cross-linking reagent, such as o-phenylenedimaleimide, to provide free maleimide groups on one partner. This partner may then be conjugated to the other by means of a thioether linkage, to give the desired F(abxe2x80x2xcex3)2 heteroconjugate (Glennie et al., 1987; incorporated herein by reference). Other approaches, such as cross-linking with SPDP or protein A may also be carried out.
Another method for producing bispecific antibodies is by the fusion of two hybridomas to form a quadroma. As used herein, the term xe2x80x9cquadromaxe2x80x9d is used to describe the productive fusion of two B cell hybridomas. Using now standard techniques, two antibody producing hybridomas are fused to give daughter cells, and those cells that have maintained the expression of both sets of clonotype immunoglobulin genes are then selected.
A preferred method of generating a quadroma involves the selection of an enzyme deficient mutant of at least one of the parental hybridomas. This first mutant hybridoma cell line is then fused to cells of a second hybridoma that had been lethally exposed, e.g., to iodoacetamide, precluding its continued survival. Cell fusion allows for the rescue of the first hybridoma by acquiring the gene for its enzyme deficiency from the lethally treated hybridoma, and the rescue of the second hybridoma through fusion to the first hybridoma. Preferred, but not required, is the fusion of immunoglobulins of the same isotype, but of a different subclass. A mixed subclass antibody permits the use if an alternative assay for the isolation of a preferred quadroma.
Microtiter identification embodiments, FACS, immunofluorescence staining, idiotype specific antibodies, antigen binding competition assays, and other methods common in the art of antibody characterization may be used to identify preferred quadromas. Following the isolation of the quadroma, the bispecific antibodies are purified away from other cell products. This may be accomplished by a variety of antibody isolation procedures, known to those skilled in the art of immunoglobulin purification (see, e.g., Antibodies: A Laboratory Manual, 1988; incorporated herein by reference). Protein A or protein G sepharose columns are preferred.
In the preparation of both immunotoxins and coaguligands, recombinant expression may be employed. The nucleic acid sequences encoding the chosen targeting agent, and toxin or coagulant, are attached in-frame in an expression vector. Recombinant expression thus results in translation of the nucleic acid to yield the desired targeting agent-toxin/coagulant compound. Chemical cross-linkers and avidin:biotin bridges may also join the therapeutic agent(s) to the targeting agent(s).
The following patents and patent applications are each incorporated herein by reference for the purposes of even further supplementing the present teachings regarding coaguligand preparation, purification and use, including bispecific antibody coaguligands: U.S. Pat. Nos. 5,855,866 and 5,877,289; U.S. applications Ser. Nos. 07/846,349; 08/350,212 (U.S. Pat. No. 5,051,230; Issue Fee paid); U.S. Ser. Nos. 08/273,567; 08/482,369; 08/485,482; and 08/472,631; 08/487,427 (U.S. Pat. No. 6,004,555; Issue Fee paid); and U.S. Ser. Nos. 08/479,727 and 08/481,904.
In certain embodiments, the vasculature of the vascularized tumor of the animal or patient to be treated may be first imaged. Generally this is achieved by first administering to the animal or patient a diagnostically effective amount of at least a first pharmaceutical composition comprising at least a first detectably-labeled aminophospholipid binding construct that binds to and identifies an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, present, expressed, translocated, presented or complexed at the luminal surface of blood vessels or intratumoral blood vessels of the vascularized tumor. The invention thus further provides compositions for use in, and methods of, distinguishing between tumor and/or intratumoral blood vessels and normal blood vessels. The xe2x80x9cdistinguishingxe2x80x9d is achieved by administering one or more of the detectably-labeledaminophosphol ipid binding constructs described.
The detectably-labeled aminophospholipid binding construct may comprise an X-ray detectable compound, such as bismuth (III), gold (III), lanthanum (III) or lead (II); a radioactive ion, such as copper67, gallium67, gallium68, indium111, indium113, iodine123, iodine125, iodine131, mercury197, mercury203, rhenium186, rhenium188, rubidium97, rubidium103, technetium99m or yttrium90; a nuclear magnetic spin-resonance isotope, such as cobalt (II), copper (II), chromium (III), dysprosium (III), erbium (III), gadolinium (III), holmium (III), iron (II), iron (III), manganese (II), neodymium (III), nickel (II), samarium (III), terbium (III), vanadium (II) or ytterbium (III); or rhodamine or fluorescein.
Pre-imaging before tumor treatment may thus be carried out by:
(a) administering to the animal or patient a diagnostically effective amount of a pharmaceutical composition comprising at least a first detectably-labeled aminophospholipid binding construct that comprises a diagnostic agent operatively attached to an antibody, binding protein or ligand, or aminophospholipid binding fragment thereof, that binds to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, present, expressed, translocated, presented or complexed at the luminal surface of blood vessels or intratumoral blood vessels of the vascularized tumor; and
(b) subsequently detecting the detectably-labeled aminophospholipid binding construct bound to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, on the luminal surface of tumor or intratumoral blood vessels, thereby obtaining an image of the tumor vasculature.
Cancer treatment may also be carried out by:
(a) forming an image of a vascularized tumor by administering to an animal or patient having a vascularized tumor a diagnostically minimal amount of at least a first detectably-labeled arninophospholipid binding construct comprising a diagnostic agent operatively attached to an antibody, binding protein or ligand, or aminophospholipid binding fragment thereof, that binds to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, on the luminal surface of tumor or intratumoral blood vessels of the vascularized tumor, thereby forming a detectable image of the tumor vasculature; and
(b) subsequently administering to the same animal or patient a therapeutically optimized amount of at least a first therapeutic agent-targeting agent construct that binds to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, on the tumor or intratumoral blood vessel luminal surface and thereby destroys the tumor vasculature.
Imaging and treatment formulations or medicaments are thus provided, which generally comprise:
(a) a first pharmaceutical composition comprising a diagnostically effective amount of a detectably-labeled aminophospholipid binding construct that comprises a detectable agent operatively attached to an antibody, binding protein or ligand, or aminophospholipid binding fragment thereof, that binds to an aminophospholipid, preferably phosphatidylserine or phosphatidylethanolamine, on the luminal surface of tumor or intratumoral blood vessels of the vascularized tumor; and
(b) a second pharmaceutical composition comprising a therapeutically effective amount of at least one therapeutic agent-targeting agent construct, preferably one that binds to phosphatidylserine or phosphatidylethanolamine.
In such methods and medicaments, advantages will be realized wherein the first and second pharmaceutical compositions comprise the same targeting agents, e.g., anti-aminophospholipid antibodies, or fragments thereof, from the same antibody preparation, or preferably, from the same antibody-producing hybridoma. The foregoing medicaments may also further comprise one or more anti-cancer agents.
In the vasculature imaging aspects of the invention, it is recognized that the administered detectably-labeled aminophospholipid binding construct, or anti-aminophospholipid antibody-detectable agent, may itself have a therapeutic effect. Whilst this would not be excluded from the invention, the amounts of the detectably-labeledconstructs to be administered would generally be chosen as xe2x80x9cdiagnostically effective amountsxe2x80x9d, which are typically lower than the amounts required for therapeutic benefit.
In the imaging embodiments, as with the therapeutics, the targeting agent may be either antibody-based or binding ligand- or binding protein-based. Although not previously connected with tumors or tumor vasculature, detectably labeled aminophospholipid binding ligand compositions are known in the art and can now, in light of this motivation and the present disclosure, be used in the present invention. The detectably-labeled annexins of U.S. Pat. No. 5,627,036; WO 95/19791; WO 95/27903; WO 95/34315; WO 96/17618; and WO 98/04294; each incorporated herein by reference; may thus be employed.
In still further embodiments, the animals or patients to be treated by the present invention are further subjected to surgery or radiotherapy, or are provided with a therapeutically effective amount of at least a first anti-cancer agent. The xe2x80x9cat least a first anti-cancer agentxe2x80x9d in this context means xe2x80x9cat least a first anti-cancer agent in addition to the therapeutic agent-targeting agent construct of the invention. The xe2x80x9cat least a first anti-cancer agentxe2x80x9d may thus be considered to be xe2x80x9cat least a second anti-cancer agentxe2x80x9d, where the therapeutic agent-targeting agent construct is a first anti-cancer agent. However, this is purely a matter of semantics, and the practical meaning will be clear to those of ordinary skill in the art.
The at least a first anti-cancer agent may be administered to the animal or patient substantially simultaneously with the therapeutic agent-targeting agent construct; such as from a single pharmaceutical composition or from two pharmaceutical compositions administered closely together.
Alternatively, the at least a first anti-cancer agent may be administered to the animal or patient at a time sequential to the administration of the at least a first therapeutic agent-targeting agent construct. xe2x80x9cAt a time sequentialxe2x80x9d, as used herein, means xe2x80x9cstaggeredxe2x80x9d, such that the at least a first anti-cancer agent is administered to the animal or patient at a time distinct to the administration of the at least a first therapeutic agent-targetingagent construct. Generally, the two agents are administered at times effectively spaced apart to allow the two agents to exert their respective therapeutic effects, i.e., they are administered at xe2x80x9cbiologically effective time intervalsxe2x80x9d.
The at least a first anti-cancer agent may be administered to the animal or patient at a biologically effective time prior to the therapeutic agent-targeting agent construct, or at a biologically effective time subsequent to the therapeutic agent-targeting agent construct. Administration of a non-aminophospholipid targeted anti-cancer agent at a therapeutically effective time subsequent to the therapeutic agent-targeting agent construct may be particularly desired wherein the anti-cancer agent is an anti-tumor cell immunotoxin designed to kill tumor cells at the outermost rim of the tumor, and/or wherein the anti-cancer agent is an anti-angiogenic agent designed to prevent micrometastasis of any remaining tumor cells. Such considerations will be known to those of skill in the art.
Administration of one or more non-aminophospholipid targeted anti-cancer agents at a therapeutically effective time prior to a therapeutic agent-targeting agent construct may be particularly employed where the anti-cancer agent is designed to increase aminophospholipid expression. This may be achieved by using anti-cancer agents that injure, or induce apoptosis in, the tumor endothelium. Exemplary anti-cancer agent include, e.g., taxol, vincristine, vinblastine, neomycin, combretastatin(s), podophyllotoxin(s), TNF-xcex1, angiostatin, endostatin, vasculostatin, xcex1vxcex23 antagonists, calcium ionophores, calcium-flux inducing agents, any derivative or prodrug thereof.
The one or more additional anti-cancer agents may be chemotherapeutic agents, radiotherapeutic agents, cytokines, anti-angiogenic agents, apoptosis-inducing agents or anti-cancer immunotoxins or coaguligands. xe2x80x9cChemotherapeutic agentsxe2x80x9d, as used herein, refer to classical chemotherapeutic agents or drugs used in the treatment of malignancies. This term is used for simplicity notwithstanding the fact that other compounds may be technically described as chemotherapeuticagents in that they exert an anti-cancereffect. However, xe2x80x9cchemotherapeuticxe2x80x9d has come to have a distinct meaning in the art and is being used according to this standard meaning.
A number of exemplary chemotherapeutic agents are described herein. Those of ordinary skill in the art will readily understand the uses and appropriate doses of chemotherapeutic agents, although the doses may well be reduced when used in combination with the present invention. A new class of drugs that may also be termed xe2x80x9cchemotherapeutic agentsxe2x80x9d are agents that induce apoptosis. Any one or more of such drugs, including genes, vectors and antisense constructs, as appropriate, may also be used in conjunction with the present invention.
Anti-cancer immunotoxins or coaguligands are further appropriate anti-cancer agents. xe2x80x9cAnti-cancer immunotoxins or coaguligandsxe2x80x9d, or targeting-agent/therapeutic agent constructs, are based upon targeting agents, including antibodies or antigen binding fragments thereof, that bind to a targetable component of a tumor cell, tumor vasculature or tumor stroma, and that are operatively attached to a therapeutic agent, generally a cytotoxic agent (immunotoxin) or coagulation factor (coaguligand). A xe2x80x9ctargetable componentxe2x80x9d of a tumor cell, tumor vasculature or tumor stroma, is preferably a surface-expressed, surface-accessible or surface-localized component, although components released from necrotic or otherwise damaged tumor cells or vascular endothelial cells may also be targeted, including cytosolic and/or nuclear tumor cell antigens.
Both antibody and non-antibody targeting agents may be used, including growth factors, such as VEGF and FGF; peptides containing the tripeptide R-G-D, that bind specifically to the tumor vasculature; and other targeting components such as annexins and related ligands.
Anti-tumor cell immunotoxins or coaguligands may comprise antibodies exemplified by the group consisting of B3 (ATCC HB 10573), 260F9 (ATCC HB 8488), D612 (ATCC HB 9796) and KS1/4, said KS1/4 antibody obtained from a cell comprising the vector pGKC2310 (NRRL B-18356) or the vector pG2A52 (NRRL B-18357).
Anti-tumor stroma immunotoxins or coaguligands will generally comprise antibodies that bind to a connective tissue component, a basement membrane component or an activated platelet component; as exemplified by binding to fibrin, RIBS or LIBS.
Anti-tumor vasculature immunotoxins or coaguligands may comprise ligands, antibodies, or fragments thereof, that bind to a surface-expressed, surface-accessible or surface-localized component of the blood transporting vessels, preferably the intratumoral blood vessels, of a vascularized tumor. Such antibodies include those that bind to surface-expressed components of intratumoral blood vessels of a vascularized tumor, including aminophospholipids themselves, and intratumoral vasculature cell surface receptors, such as endoglin (TEC-4 and TEC-11 antibodies), a TGFxcex2, receptor, E-selectin, P-selectin, VCAM-1, ICAM-1, PSMA, a VEGF/VPF receptor, an FGF receptor, a TIE, xcex1vxcex23 integrin, pleiotropin, endosialin and MHC Class II proteins. The antibodies may also bind to cytokine-inducible or coagulant-inducible components of intratumoral blood vessels.
Other anti-tumor vasculature immunotoxins or coaguligands may comprise antibodies, or fragments thereof, that bind to a ligand or growth factor that binds to an intratumoral vasculature cell surface receptor. Such antibodies include those that bind to VEGF/VPF (GV39 and GV97 antibodies), FGF, TGFxcex2, a ligand that binds to a TIE, a tumor-associated fibronectin isoform, scatter factor/hepatocyte growth factor (HGF), platelet factor 4 (PF4), PDGF and TIMP. The antibodies, or fragments thereof, may also bind to a ligand:receptor complex or a growth factor:receptor complex, but not to the ligand or growth factor, or to the receptor, when the ligand or growth factor or the receptor is not in the ligand:receptor or growth factor:receptor complex.
Anti-tumor cell, anti-tumor stroma or anti-tumor vasculature antibody-therapeutic agent constructs may comprise cytotoxic agents such as plant-, fungus- or bacteria-derived toxins (immunotoxins). Ricin A chain and deglycosylated ricin A chain will often be preferred, and gelonin and angiopoietins are also contemplated. Anti-tumor cell, anti-tumor stroma or anti-tumor vasculature antibody-therapeutic agent constructs may comprise coagulation factors or second antibody binding regions that bind to coagulation factors (coaguligands). The operative association with Tissue Factor or Tissue Factor derivatives, such as truncated Tissue Factor, will often be preferred.
The invention still further provides a series of novel therapeutic binding ligands, binding ligand compositions and pharmaceutical compositions, each of which comprise at least a first targeting agent that binds to an aminophospholipid, operatively attached to at least a first therapeutic agent, such as a cytotoxin, anti-angiogenic agent or coagulant. Radiolabels are generally excluded from the binding ligands and binding ligand compositions; although not from the diagnostic methods, or even from the therapeutic methods described above.
The targeting agents of the binding ligands preferably bind to phosphatidylethanolamine and/or phosphatidylserine. The entire range of binding ligands described above in the context of the therapeutic and combined methods may be employed in the present compositions. Annexin conjugates and constructs; anti-PS, anti-PE, human, humanized and monoclonal antibody conjugates and constructs; ricin conjugates; and Tissue Factor conjugates and constructs are currently preferred. Compositions comprising one or more anti-PS antibodies operatively attached to one or more Tissue Factor derivatives, preferably, truncated Tissue Factor, are currently particularly preferred.
Direct or indirect attachment and linkages may be employed in the binding ligand compositions, including all variations of bispecific antibodies. Operative combinations of a first antigen-binding region of an antibody that binds to an arninophospholipid, with a second antigen-binding region of an antibody that binds Tissue Factor or a Tissue Factor derivative are also preferred. In the aminophospholipid binding protein constructs or conjugates, annexins are preferred, with Annexin V being more preferred, and Annexin V operatively attached to truncated Tissue Factor currently being most preferred.
Components of the invention therefore include an antibody construct, comprising at least a first anti-aminophospholipid antibody, or antigen-binding fragment thereof, operatively attached to at least a first therapeutic agent; and a bispecific antibody, comprising a first antigen-binding region that binds to an aminophospholipid operatively attached to a second antigen-binding region that binds to a therapeutic agent.
The compositions and pharmaceutical compositions may comprise at least a first and second binding ligand that each comprise at least a first targeting agent operatively attached to at least a first therapeutic agent; wherein each targeting agent binds to an aminophospholipid. Compositions and pharmaceutical compositions that comprise at least a first binding ligand that binds to phosphatidylethanolamine and at least a second binding ligand that binds to phosphatidylserine are exemplary combined compositions.
The present invention yet further provides a series of novel therapeutic kits, medicaments and/or cocktails for use in conjunction with the methods of the invention. The kits, medicaments and/or cocktails generally comprise a combined effective amount of an anti-cancer agent and a therapeutic agent-targeting agent construct, preferably one that binds to phosphatidylserine or phosphatidylethanolamine. Imaging components may also be included.
The kits and medicaments will comprise, preferably in suitable container means, a biologically effective amount of at least a first therapeutic agent-targeting agent construct, preferably binding to phosphatidylserine or phosphatidylethanolamine; in combination with a biologically effective amount of at least a first anti-cancer agent. The components of the kits and medicaments may be comprised within a single container or container means, or comprised within distinct containers or container means. The cocktails will generally be admixed together for combined use.
The entire range of therapeutic agent-targeting agent construct, as described above, may be employed in the kits, medicaments and/or cocktails, with annexin conjugates and constructs; anti-PS, anti-PE, human, humanized and monoclonal antibody conjugates and constructs; ricin conjugates; and Tissue Factor conjugates and constructs being preferred. The anti-cancer agents are also those as described above, including chemotherapeutic agents, radiotherapeutic agents, anti-angiogenic agents, apoptopic agents, immunotoxins and coaguligands. Agents formulated for intravenous administration will often be preferred.